1. Field of the Invention
The present invention relates to protecting wiring from excessive current in automotive vehicles
2. Background Art
Automotive vehicles include a wide range of electrical devices powered by a battery, generator, alternator, fuel cell, and the like. These electrical devices vary in characteristics and functions. For example, automotive vehicles can include various lamps, heating elements, electrical motors, storage devices, electronic modules, powered sensors, and the like. Each electrical device is connected to a source of electrical power through wiring. This wiring must be correctly sized to supply current to the load over various operating conditions.
Current flowing through the wiring may exceed expected values due to various conditions such as, for example, a short circuit in the system, load failure, operation of the electrical device in an unexpected manor, alteration of the electrical device or unanticipated addition of electrical load by the operator, damage due to an accident involving the automotive vehicle, and the like. Under such conditions, excessive current in the wiring may cause the wiring to fail.
Often, wiring is the least capable component in an electrical system. Therefore, traditionally, wiring has been protected from excessive current by placing a fuse in the wiring circuit. One problem with a fuse is that, once it blows, it must be replaced, creating an inconvenience for the operator. Another problem with a fuse is that it is not adjustable for changes in operating conditions. Yet another problem is difficulty protecting from both short duration, high current events and long duration, low current events.
Recently fuses have been replaced by solid state switches. These switches may be reset following an episode of excessive current. Solid state switches have been packaged with current sensors, temperature sensors, current flow timers, and support electronics for determining when to interrupt the flow of current. However, these systems have not been responsive to changes in operating conditions and may suffer from an ability to handle different types of overcurrent events.